1,3-benzoxazine-2-thiones

ABSTRACT

Described are 1,3-benzoxazine-2-thiones of the formula   WHEREIN R and R&#39;&#39; are selected from the group consisting of hydrogen, methyl and ethyl. The following compounds come within the above formula: 3,4-dihydro-2-thioxo-2H-1,3-benzoxazine-3acetamide; 3,4-dihydro- Alpha -methyl-2-thioxo-2H-1,3benzoxazine-3-acetamide; 3,4-dihydro-4-methyl-2-thioxo-2H-1,3benzoxazines-3-acetamide. Also described is a process for preparing the compounds which display antidepressant properties.

United States Patent [72] Inventors LuiglBernardi;

Severina Coda; Giselbert Karl Suchowsky; Lorenzo Pegrassi, all of Milan, Italy [21] Appl. No. 725,513

[22] Filed Apr. 30, 1968 [45] Patented Dec. [4, 1971 73] Assignee Socleta Farmaceutici Italla Milan, Italy [32] Priority July 25, 1967 [33] Italy [54] l,3-BENZOXAZlNE-2-THIONES 4 Claims, No Drawings [52] [1.8. CI. 260/244 R, 260/471 A, 260/519, 424/248 [51] lnt.Cl ..C07d 87/14 [50] Field of Search 260/244 [56] References Cited UNITED STATES PATENTS 2,326,732 8/1943 Fisher 260/244 3,427,313 2/1969 Bemardi et al. 260/244 3,446,804 5/1969 Shave] et a1 260/244 FOREIGN PATENTS 1,003,] 13 9/1965 Great Britain 260/244 OTHER REFERENCES Chemical Abstracts Subject Index, A- J, Vol. 70, pages 488 S- 489 S (1969). QD1.A51

Chemical Abstracts Seventh Collective lndex Subjects Hy-Lit Volumes 56-65, page 11,576 S 1970). QDLASI Chemical Abstracts Subject Index, A- K, Vol. 69, page 479 S (July- December, 1968,- 1969), QD1.A51

Burger Medicinal Chemistry, 2nd ed., N.Y., pages 77-78, lnterscience, 1968 RS403.B8

ABSTRACT: Described are l,3-benzoxazine-2-thiones of the formula wherein R and R'are selected from the group consisting of hydrogen, methyl and ethyl. The following compounds come within the above formula: 3,4-dihydro-2-thioxo-2H-1,3- benzoxazine-Ii-acetamide; 3,4-dihydro-a-methyl-2-thioxo-2H- l,3-benzoxazine-3-acetamide; 3,4-dihydro-4-methyl-2-thioxo- 21-1-1 ,3-benzoxazines-3-acetamide. Also described is a process for preparing the compounds which display antidepressant properties.

1,3-BENZOXAZINE-2-THIONES I disappears within 4-5 hours.

Table 1 lists the data of the antidepressive activity of 3,4- Our present invention relates to 1,3-benzoxazine-2-thiones dihydro-2-thioxo-2H-l,3-benzoxazine-3-acetamide in mice and the process for the preparation thereof. In particular our with respect to reserpine. This activity is also compared to the invention has an object 1,3-benzoxazine-2-thiones of the 5 antidepressive activity shown by imipramine with respect to structure reserpine.

TABLE 1 Rectal temper. Doses, Administration eture, Compound mgJkg. route Ptosis in C 37. 40 32. 1 29 36. 2 3,4-dihydr0-2-thioxo-2 25 36. 6 B-acetamide plus B. 87 5 3,4-dihydro-2-thioxo-2H-1,8-benzoxa- 100.0 zine-a-acetamide plus B. 1

Examination of the data in table 1 shows that the compound 0 S of the invention, at the same dosage of 50 mg./kg. is as active as imipramine. However, the dose of 50 mg./kg. in-

NCH--00NH2 traperitoneal is the highest tolerated dose for imipramine,

whereas 3,4-dihydro-2-thioxo-2H- l ,3-benzoxazine-3-acetamide is tolerated to dose of 300 mg./kg. intraperitoneal. Nor- R wherein R and R are selected from th group consisting ot 3 2 52? fg iz animals ls already observed at a hydrogen, methyl and ethyl; and the process for their preparation. The compounds of our invention display interesting pharmacological activities and may be usefully employed as antidepressants.

Our process for the preparation of the new 1,3-benzoxazine-2-thiones consists in reacting a lower alkyl ester of ohydroxy-phenyl-alkylamino-alkylcarboxylic acid with a suitable sulphurated compound to give the optionally-4-substituted The antireserpine action has been also tested on a macaco rhesus monkey (weight 3.l00 kg). The animal was injected with 3,4-dihydro-2-thioxo-2H-benzoxazine-3-acetamide at a dose of 25 mg./kg. intramuscular and, 3 hours after the treatment, was injected with 0.75 mg./kg. of reserpine intramuscular. It has been observed that the reserpine syndrome was completely antagonized by the compound of the invention.

3-carboalkoxy-alkyl-,3-benzoxazin-2-thione which is The anti-amin-oxidase (antiJviAO) activity has been stusaponified to the free acid and then transformed into the cordied in vivo and in vitro on hepatic and cerebral mitochondria responding amide according to the following reaction scheme I of rats. inhibiting concentration (lC in vitro is the molar OH O\ oyolization S NH-CH-COOR NCH-GOOR" 311 R R R R IV saponiflcation III :8 8 amidation N-CH-COOH N-CH-CONH,

II I

wherein R and R are selected from the group consisting of concentration of the substance able to reduce 50 percent of hydrogen, methyl and ethyl, and R" is alkyl having from one the mitochondrial monoaminoxidase activity. inhibiting dose to four carbon atoms. 50(lD in vivo is the quantity of the substance able to reduce More particularly, the alkyl ester IV dissolved in a solvent 50 percent of the mitochondrial monoaminoxidase activity.

such as tetrahydrofurane, benzene or diethyl ether is made to The data obtained are reported in table 2. react with a suitable sulphurated agent such as thiophosgene,

carbon disulphide or carbonylthiodiirnidazole in the presence TABLE 2 of a condensing agent such as pyridine triethylamine or I it InIrgvo diethylamine. The cyclized compound Ill after being purified Organ Inhibiting compound 2 7 3 mglkglff and crystallized rs dissolved in a solvent, such as an aliphatic Li I m id (H 1 5 alcohol having from one to four carbon atoms, saponified with gg y gj j 'fi ;5; ag 3 alkali and then dissolved in a suitable solvent. To the solution B in ben zoxazlne-a-acetamide. 6 an excess of ammonia in the presence of dicyclohexylcarbodiim gg lg gggxfifiajfiiz: mide optionally together with N-hydroxy-succinrmlde ts benzoxazine-a-acetamlde.

added. The amide l separates by crystallization as a crystalline ,Inactive' solid stable to light and heat. I

The compounds of the invention show an interesting activi- F m he a o ta It can b ded at 3. -d hy ty in reventin the d re ion i d d b reserpine, I thioxo-ZH-l,3-benzoxazine-3-acetamide shows in vitro a certicular, tests have been performed using the 3,4-dihydro-2- tain antimonoaminoxidase activity. This activity could be exthioxo-Zl-l-l,3-benzoxazine-3-acetamide which confirm its efplained by a direct action of the product on mitochondria. in fectiveness in preventing the blepharoptosis induced by reservivo this activity is absent. pine and in normalizing the hypothermia. Such a compound The acute toxicity (LD of 3,4-dihydro-2-thioxo-2H-1,3-

induces in mice, when administered at high doses (300-1,000 benzoxazine-B-acetamide determined on albino male mice mgJkg. per 0s) a clinical pattern of sedation which however (weight about 20 g.) by oral route has been determined 48 TABLE 3 5 DL mgJkg.

per 05 Compound lmipramine 3,4-dihydro-Z-thioxo-2H- l ,3-benzoxazine-3-acetamlde The antidepressive effect of 3,4-dihydro-2-thioxo-2H-1,3- benzoxazine-IS-acetamide in respect to reserpine has furthermore been studied for observing the normalization of behavior which the administration of this compound causes in a swimming reserpinized rat. The experiment consists in putting the animal into a basin full of water and measuring the time taken by the rat to swim to the edge of and to leave the basin.

A nontreated rat generally takes 7-8 seconds to overcome this test. The reserpinized rat swims irregularly. This swimming consists in movements which allow the animal to remain afloat only. ln those cases in which the animal is successful to safely exit, the time spent is much higher. Table 4 reports the data obtained from this experiment. The test has been carried out 5 hours after the administration of the compounds under examination.

TABLE 4 Average Dose, time to get Number mg./kg., out of the v of animals lntrabasin (in which do not Compound peritoneal seoonds) get out 3 5 Controls 7 Reserpine (R) 5 Iml ramine plus B 25 7 3,4 lhydro-2thioxo-2H-1,3- 25 7 0/ benzoxazlne-B-acetamlde plus R.

40 The following examples serve to illustrate the invention without limiting it.

EXAMPLE I 3 ,4-dihydro-2-thioxo-2H- 1 ,3-benzoxazine-3-acetamide A solution of 5.9 cc. of thiophosgene in 20 cc. of tetrahydrofurane is added to 10 g. of ethyl ohydroxybenzylamino-acetate dissolved in 60 cc. of tetrahydrofurane. After half an hour the solvent is evaporated off almost to dryness. 21.5 cc. of triethylamine diluted with an equal volume of tetrahydrofurane are added to the residue. This mixture is kept for half an hour under stirring, evaporated, the residue taken up with water and the oily phase extracted with chloroform. The residue of the extraction is purified by chromatography of alumina. Five grams of ethyl 3,4-dihydro2- thioxo-ZH-l,3-benzoxazine-3-acetate as white crystals, melting at 67-70 C., are obtained. Five grams of this compound are dissolved in 100 cc. ethyl alcohol and saponified at room temperature with 20 cc. of N-sodium hydroxide. The ethyl alcohol is evaporated and the aqueous solution acidified to give 3.7 g. of 3,4-dihydro-2-thioxo-2H-l ,3-benzoxazine-3-acetic acid melting at 17 l-l 73 C. Three grams of this acid are dissolved in the smallest amount of tetrahydrofurane. An equivalent of an alcoholic solution of ammonia is then added, whereby the ammonium salt of 3,4-dihydro-2-thioxo-2H-1,3- benzoxazine-3-acetic acid precipitates. It is first dried, then dissolved in 65 cc. of dimethylformamide at 5060 C. A half equivalent of an alcoholic solution of ammonia, 3 g. of N- hydroxy-succinimide and 2.85 g. of dicyclohexylcarbodiimide are added to the cooled solution. The mixture is stirred for a few hours, the precipitated dicyclohexylurea filtered off and the filtrate evaporated to dryness. The residue is taken up with ethyl alcohol/diethyl ether whereby 2 g. of 3,4-dihydro-2- thioxo-Zl-L1,3-benzoxazine-3-acetamide as very thin white crystals, melting at 232-235 C., are obtained.

EXAMPLE 2 3 ,4-dihydro-a-methyl-2-thioxo-2H- l ,3-benzoxazine-3- acetamide The operation is carried out as described in example I with the difference that the starting material consists of ethyl 3,4- dihydro-a-methyl-2-thioxo-2H-l ,3-benzoxazine-3-acetate from which by cyclization 4H-3( l '-carboethoxyethyl)-l,3- benzoxazin-Z-thione is formed. By successive saponification and amidation 3,4-dihydro-a-methyl-2-thioxo-ZH- l ,3-benzoxazine3-acetamide is obtained.

EXAMPLE 3 3,4-dihydro-4-methyl-2-thioxo-2H-l ,3-benzoxazine-3- acetamide N-CH-CONHz wherein R and R are selected from the group consisting of hydrogen, methyl and ethyl.

2. The compound of claim 1, which is 3,4-dihydro-2-thioxo- 2H- 1 ,3-benzoxazine-3-acetamide.

3. The compound of claim 1, which is 3,4-dihydro-amethyl-2-thioxo-2H-l ,3-benzoxazine-3-acetamide.

4. The compound of claim 1, which is 3,4-dihydro-4 methyl-Z-thioxo-ZH- l ,3-benzoxazine-3 -acetamide. 

2. The compound of claim 1, which is 3,4-dihydro-2-thioxo-2H-1, 3-benzoxazine-3-acetamide.
 3. The compound of claim 1, which is 3,4-dihydro- Alpha -methyl-2-thioxo-2H-1,3-benzoxazine-3-acetamide.
 4. The compound of claim 1, which is 3,4-dihydro-4-methyl-2-thioxo-2H-1,3-benzoxazine-3-acetamide. 